In another game show there were 20 doors. The host opened 18 doors and they all had lemons behind them. Are you better off switching doors now?
How about if there were 5000 doors with 4998 lemons? In all cases two doors remain, one lemon, one money. Remaining where you are gives you the same chance as changing.
Benard - pressed for time at present so I'll just say that the contestant would be advised to swap doors whatever the parameters. Explanation to follow but, if you want to find out before I get back from holiday, read "The Curious Incident of the Dog in the Night-time. It'll provide the answer and it's a cracking good read, offering an insight into the life of a young man towards the milder end of the autistic spectrum.